"Individuals tested positive more than once are only counted once, on the date of their first positive test."

[WindFlower92]

Found on the gov website. Are we not tracking if people can get reinfected then? How can we have data on this if we don't recognise it? I know there's only been a handful of reinfections worldwide, but surely this is key to understanding herd immunity?

Link

coronavirus.data.gov.uk/cases?areaType=ltla&areaName=Portsmouth

Most people are only infectious for about 10 days. But they can test positive (from that single infection) for up to 4 weeks afterwards even if was a mild case.

Double counting people and infections is worse danger for data analysis than missing the rare double infection because it happened in a small time frame (say 6 weeks from 1st to 2nd). Eventually some rule of thumb will emerge, like (maybe) if the gap was at least 6 weeks then we can call it a separate infection event. Genomics is useful, too, then can identify different strains so know if the bout truly was separate.

Bit like it took a while to decide that for covid to be identified as primary cause of death the death should occur within 28 days of the positive test not 6 months later -- hence the summary needs to use earliest positive test date, not the repeat test results 2 or 7 or 14 days after the first test.

Good points, thanks for the explanation @MedSchoolRat!

A lot of people in hospital get multiple years for one case as well. E.g if you live is a care home you have to be tested weekly until negative to go home. There are patients that have 6 or 7 tests that are all positive but only had one episode of covid